In many amplification and signal processing applications, a premium is placed on preserving the integrity of the signal as the signal undergoes various electronic processes. One of the most significant causes of signal degradation is the introduction of noise, which can be the result of any number of electronic and physical processes. Accordingly, circuit designers are constantly attempting to determine the mechanisms by which noise is coupled into a circuit and techniques for reducing that noise to the lowest possible level within the confines of cost and circuit complexity.
For certain types of electronic circuits, such as those used to amplify outputs from condenser microphones and accelerometers that employ piezoelectric or Micro Electro-Mechanical Systems technology, reducing the level of noise coupled into and generated by the various circuit elements can be especially problematic. In these instances, the signal source may have a large output impedance which can cause the output signal to be particularly susceptible to the introduction of noise brought about by the loading effects of subsequent signal processing circuitry. Accordingly, designing and building circuits that can receive and process these types of signals is a continued area of investigation.